CVE-2026-31740

Local device disruption via shared pointer race

Published May 1, 2026 · Updated May 1, 2026

Race condition in the Linux Kernel 6.4 rz-mtu3 counter driver allows local users to disrupt devices through misdirected runtime PM. The counter and PWM subdrivers overwrite the same rz_mtu3_channel.dev pointer for channels 1 and 2, so probe order can leave the counter driver operating on the PWM driver's device instance. Reachability requires both RZ/G2L MTU3 subdrivers to share those channels; the bounded effect is wrong-device power-management activity.

CVSS severity5.5
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Race condition in the Linux Kernel 6.4 rz-mtu3 counter driver allows local users to disrupt devices through misdirected runtime PM. The counter and PWM subdrivers overwrite the same rz_mtu3_channel.dev pointer for channels 1 and 2, so probe order can leave the counter driver operating on the PWM driver's device instance. Reachability requires both RZ/G2L MTU3 subdrivers to share those channels; the bounded effect is wrong-device power-management activity.

The record

CVE
CVE-2026-31740
Published
May 1, 2026
Updated
May 1, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 1, 2026CVE publishedPublication date reported by the CVE source.
  2. May 1, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0be8907359df4c62319f5cb2c6981ff0d9ebf35a <28a371be901ef44ee03726c2575d7d6795521fe0
  2. Affected versionversion=0be8907359df4c62319f5cb2c6981ff0d9ebf35a <2932095c114b98cbb40ccf34fc00d613cb17cead
  3. Affected versionversion=0be8907359df4c62319f5cb2c6981ff0d9ebf35a <633dfbf0eb2766c597c1a59dd83035c82e14791d
  4. Affected versionversion=0be8907359df4c62319f5cb2c6981ff0d9ebf35a <63be324c795262f0e316c6fe9b329d83afa1ec93
  5. Affected versionversion=0be8907359df4c62319f5cb2c6981ff0d9ebf35a <6562290225c197e2e193a53de2a517815288dcd1
  6. Affected versionversion=6.4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=0be8907359df4c62319f5cb2c6981ff0d9ebf35a <28a371be901ef44ee03726c2575d7d6795521fe0; version=0be8907359df4c62319f5cb2c6981ff0d9ebf35a <2932095c114b98cbb40ccf34fc00d613cb17cead; version=0be8907359df4c62319f5cb2c6981ff0d9ebf35a <633dfbf0eb2766c597c1a59dd83035c82e14791d; version=0be8907359df4c62319f5cb2c6981ff0d9ebf35a <63be324c795262f0e316c6fe9b329d83afa1ec93; version=0be8907359df4c62319f5cb2c6981ff0d9ebf35a <6562290225c197e2e193a53de2a517815288dcd1; version=6.4

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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